GaN基高压直流发光二极管制备及其性能分析

GaN基高压直流发光二极管工艺制备, 采用蓝宝石图形衬底(PSS) 外延片制备正梯形芯粒结构的GaN基高压直流LED.相对其他结构器件, 该结构器件发光效率最高, 封装白光后, 在色温4500 K, 驱动电流20 mA时, 光效116.06 lm/W, 对应电压50 V. 测试其I-V曲线表明, 开启电压为36 V, 对应驱动电流为1.5 mA; 在电流15 mA至50 mA时, 光功率随驱动电流增加近似于线性增加, 在此区域光效随电流增加而降低的幅度比较缓慢, 表明GaN基高压直流LED适宜于采用大电流密度驱动, 而不会出现驱动电流密度增加导致量子效率明显下降(efficiency droop), 为从芯片层面研究解决量子效率下降难题提供了一种新思路.     

Micro-light-emitting-diode array with dual functions of visible light communication and illumination

We demonstrate high-speed blue 4 × 4 micro-light-emitting-diode(LED) arrays with 14 light-emitting units(two light-emitting units are used as the positive and negative electrodes for power supply, respectively) comprising multiple quantum wells formed of Ga N epitaxial layers grown on a sapphire substrate, and experimentally test their applicability for being used as VLC transmitters and illuminations. The micro-LED arrays provide a maximum-3-d B frequency response of 60.5 MHz with a smooth frequency curve from 1 MHz to 500 MHz for an optical output power of 165 mW at an injection current of 30 mA, which, to our knowledge, is the highest response frequency ever reported for blue Ga N-based LEDs operating at that level of optical output power. The relationship between the frequency and size of the device single pixel diameter reveals the relationship between the response frequency and diffusion capacitance of the device.